This invention relates to an engine with a turbo-charger and more particularly to an improved arrangement for turbo-charging and intercooling an internal combustion engine in such a manner that it may be used as the power unit of an outboard motor.
The use of turbo-chargers to improve the performance of an internal combustion engine is well known. The turbo-charger includes a turbine stage which is driven by the engine exhaust gases and which drives a compressor stage for compressing the air charge delivered to the engine induction system. Because the compressor stage compresses the intake charge, however, it also tends to raise the temperature of the intake charge and thus offsets some of the advantages of its utilization. In order to avoid this temperature raise and loss of volumetric efficiency, it has been proposed to employ an intercooler for cooling a compressed air charge before it is delivered to the engine induction system.
A specific application of turbo-charging may be found in the power unit of an outboard motor. Such power units are normally two-cycle engines and these engines adapt themselves particularly to turbo-charging. In addition, the very nature of an outboard motor requires that the power unit be very small and yet develop a relative high amount of horsepower for a given size. However, with the additional of an intercooler, it becomes very difficult to position all of the components for the engine. In addition, if the engine employs an air silencer, the turbo-charger must be separately positioned and conduits need to be provided in order to deliver air to the intercooler and air from the intercooler to the air silencer. In addition. hose connections are required for delivering coolant to the intercooler and these connections, particularly the pressure connections on the air side, if they fail, can cause significant problems.
It is, therefore, a principal object of this invention to provide an improved and compact arrangement for turbo-charging and intercooling an internal combustion engine.
It is a further object of this invention to provide an arrangement wherein an engine having an air inlet device may be intercooled through the use of an intercooler that is formed integrally with the air inlet device and thus reduce the amount of external hose connections that are required.